Electrical properties of SrTiO3/BaTiO3 strained superlattice films prepared by atomic layer metallorganic chemical vapor deposition

SrTiO3/BaTiO3 dielectric superlattice films with various periods were prepared by atomic layer metallorganic chemical vapor deposition. The electrical properties of these superlattice films were characterized via a series of electrical measurements to demonstrate that dielectric properties can be artificially controlled by fixing the superlattice period and, as a result, a dielectric constant as large as over 450 can be obtained. This is because polarization is strongly affected by stress, which arises from the lattice mismatch of superlattice layers. Such effects are dramatic. especially in the case of a short period of less than 10/10 monolayers. Based on transmission electron microscope cross-sectional observations and electrical measurements, the leakage current of the superlattice films is primarily due to defects and oxygen vacancies. The leakage current density decreased below 10(-6) A/cm(2) at 2 V after annealing in oxygen at 700 degreesC for 2 h. (C) 2000 The Electrochemical Society. S0013-4651(00)03-056-1. All rights reserved.